The goals of this program are to extend our understanding of the biology and application of dendritic cells (DC) in tumor immunology. In each project there is a fundamental need to define the potential role of DCs in these processes. The role(s) of the imaging core are diverse. In summary we will examine protein uptake, trafficking and expression by dendritic cells, examine dendritic cell trafficking and location within tissue systems, investigate cell-cell interactions between DCs, T-cells, and other effector cells, use histology and quantitative histochemistry to measure specific inflammatory processes. These investigations span the entire resolution spectrum of optical microscopic tools, from low resolution studies of whole tissues, to high resolution observations of subcellular compartments. The Center for Biologic Imaging, in which this core service will be performed, is equipped to perform a continuum of optical methods including all types of light and electron microscopy essential to this program. During the previous funding cycle this core has proven to be an invaluable resource, as is demonstrated by collaborative publication and described in the preliminary data section below. This core has and will continue to be used extensively by all projects. Furthermore the current and future research goals of the program have led to the development of program specific imaging tools and have leveraged the acquisition of large instrumentation grants as well as the construction of imaging tools specifically directed to this program. In the previous submission of this proposal, this core was rated as Superior, with no criticism of core function and utility. As such the changes to this aspect of the proposal are minor. The principal changes are the removal of interactions and preliminary data relating to the two projects that have been removed from the proposal.